This invention relates to roller track conveying apparatus for conveying cargo loads.
Of interest are U.S. Pat. Nos. 4,909,378, 4,750,604, 4,909,372, 4,036,345 and 4,089,399 all incorporated by reference herein.
These patents relate to roller track mechanical handling systems in which an outer elongated channel receives an elongated inflatable air bag along the channel length. The air bag is supplied with pressurized air to selectively inflate or deflate the bag. A second inner elongated channel is nested within the outer channel. A series array of rollers are rotatably secured to the inner channel and are aligned with openings in a top plate secured over the outer channel. The inner channel rests on the air bag and is raised and lowered within the outer channel as the air bag is inflated and deflated. This raises the rollers to an exposed operative position extending above the top plate to receive cargo to be displaced. When the bag is deflated, the rollers are recessed into the outer channel below the top plate permitting the cargo to rest on the top plate of the assembly and become relatively difficult to displace and stationary due to high frictional resistance with the plate. A pressurized air line is coupled to the end track air bag to selectively pressurize and deflate the air bags.
Typically, a series of such tracks are installed end to end to form a continuous linear track. A fitting is connected to the end air bag to receive a pressurized inlet air line from a pressurized air source and also to supply pressurized air to a further air line which feeds pressurized air to the immediate aligned next adjacent track via fittings coupled to each air bag. In similar fashion, a further air line feeds air to the next successive one of the series of aligned tracks.
The air bag is clamped by one clamp at the air inlet region and includes a fitting attached to the air bag by the clamp. The fitting extends outside the outer channel to receive the inlet pressurized air. The bag is long and the other end is also clamped, e.g., by two plates that are bolted together and has no air fitting. This clamped end is free to move about in any direction and may at times displace longitudinally which is undesirable. The problem with this arrangement is that the free end of the air bag with only a clamp tends to fold over onto itself because the deflated bag is flat. This fold over condition interferes with operation of the air bag during inflation. Also, the folds tend to become fatigued due to the inflation and deflation cycles.
In a another arrangement of the prior art, the end without the fitting is attached to the top plate by a vertical bar that is fixed to the top plate and to the air bag clamp. This structure involves additional parts which add difficulty for the assembly process and thus also add cost.
These problems are solved by the present invention.
A roller conveying apparatus according to the present invention comprises an outer channel member having a bottom wall and two opposing side walls forming an elongated receptacle; a top plate secured to the outer channel member side walls for enclosing the receptacle, the top plate having a plurality of openings there through; an inner channel member having a bottom wall and forming an elongated inner channel, the inner channel member being disposed in the receptacle; a plurality of rollers for vertically supporting a cargo load and rotatably secured to the inner channel member in the inner channel, each roller corresponding to a roller receiving opening in the top plate; an elongated inflatable air bag in the receptacle disposed between and for engagement with the outer channel member bottom wall and the inner channel member bottom wall, the air bag when inflated for displacing the inner channel member in a vertical direction to move the rollers through the corresponding openings and when deflated for permitting displacement of the inner channel member to recess the rollers into the inner channel member channel, the air bag having first and second opposing ends and being arranged to receive pressurized air to inflate the bag; a clamp at one of the air bag ends for sealing the air bag one end, the clamp for displacing in the receptacle in response to the inflation and deflation of the air bag; and guide means for guiding the clamp during the clamp displacement.
In one aspect, the guide means comprises cooperating means coupled to the clamp and outer channel member arranged to permit only vertical displacement of the clamp in the receptacle.
In a further aspect, the outer channel member side walls each have a slot, the clamp comprising at least one member for fluid sealing the air bag one end, the at least one member having opposing first and second ends, the at least one member first and second ends each including a tab for engaging and mating with the slot in a corresponding different outer channel member side wall.
In a further aspect, the slots are oriented vertically in the corresponding outer channel member side wall, the tab for traversing the mating slot vertically.
In a still further aspect, the clamp comprises a pair of plates fastened together, each plate having opposing ends and lying in a plane, the guide means including a tab extending from at least one end of at least one of the plates, at least one outer channel member side wall having a slot for receiving the tab to permit the clamp to displace vertically in response to inflation and deflation of the air bag while precluding horizontal displacement of the bag one end.
In a further aspect, the guide means is arranged to prevent horizontal displacement of the air bag one end.
In a further aspect, the guide means comprises matingly engaged means coupled to the clamp and outer channel member for permitting vertical displacement while precluding horizontal displacement of the air bag one end.
Preferably, the guide means comprises a tab on the clamp and a mating slot for receiving the tab in a side wall of the outer channel member.
In a further aspect, the clamped end opposite the end with the fitting comprises two plates one of which has opposing end tabs. The outer channel has mirror image aligned vertical slots in the opposing side walls for receiving the tabs, a tab being located in a corresponding slot. In this way the clamped end can ride up and down vertically with the air bag as it is inflated and deflated, minimizing damage to the air bag, while at the same time keeping the bag end in fixed axial position in the outer channel with a minimum of parts.